Improvement in pistons for steam-engines



Nirnn STATES f PATENT OFFICE.

F'. H. FURNISS AND JACOB HOVEY, OF CLEVELAND, OHIO.

IMPROVEMENT IN PISTONS FOR STEAM-ENGINES.

Fdpeccatinnforming part of Letters Patent No. 40,559, dated November 10, 1863.

To all whom t may concern:

Be it known that we, F.1H. FURNIss and J. HovEY, of Cleveland, county of Cuyahoga, and State of Ohio, have invented a certain Improved Steam-Engine Piston 5 and we do hereby decla-re that the following is a full and exact description ofthe same, reference being had to the accompanying drawings, making part of this specification, in which- Figure l is a side or face view of the piston.

Fig. 2 is an end view. Fig. 3 represents thel opposite side from Fig. l. Fig. 4 is a section in the direction ofthe line w in Fig. 2. Fig. 5 is a section in the direction of the line .r in Fig. 2. Figs. 7, 8, and 9 are detached sections, which will be referred to in description.

Like letters denote like parts in t-he drawlugs.

The nature of our improvement relates to a piston so constructed and arranged that the packing-rings when in the cylinder will be eX- tended so as to fit the bore of the cylinder steam-tight by the action of the steam admitted into the cylinder for the purpose of working the engine, and also in the employment of certain devices for adjusting the packing to the bore ot' the cylinder, as the nature of the case may require.

A and-B, Figs. 1,2, and 3, are the followers on each side of the piston, and secured together by the screws c.

The spring-packing C maybe constructed in the ordinary manner.

D is the piston-rod.

The piston, Figs. 4, 5, and 6, is constructed with openings E and F, which in number may be more or less, as the nature of the case may require. The openings herein described are three on each side, which pass into the middle or center of the piston G, then turn at right vangles out through the periphery of the piston, as seen in Figs. 4, 5, and 6. The openings from the periphery are enlarged, forming chambers and a shoulder or valve-seat at the junction of the small openings, as indicated at H. This large part of the openings receives the thimble-valves I, which rest, respectively, upon the seat H. The openings are alike on each side, and which communicate with the valves in the chambers. There are also openings in the followers, which are in direct line with the openings in the piston, as seen in Fig. 5. The chambers and valves ra- The valves are operated by means of the y steam passing in at the side openings, which forces out the valves, so as to act on the under side of the packing C, causing-it to expand, thereby perfectly fitting the bore of the cylinder, thus preventing the passage of steam between the cylinder and-packing as the pis- When the piston is in action, the steam will only pass 1u at the openton reciprocates.

ings on one side at a time. If moving in the direction ofthe arrow in Fig. 5, the steam passes in at the openings E, forcing out the valves I I', and when moving in a reverse direction the steam enters in the openings F and operates the valves in the manner and for the same purpose as before mentioned. There being an equal number of valves acting upon the packing at all times when in motion, it follows that in this way the packing is eX- panded alike as the piston is moved in either direction. When the piston is receiving steam upon one side, and should it by any means force a passage through the valvechambers, or otherwise enter and occupy the space between the packing and the periphery1 of the piston, the steam will not affect the valves receiving the action steam, while the valves on the exhaust side will be pressed down upon their respective valveseats, thus ei'ectually cutting off all passage of steam through the piston. This arrangement allows the valves to be of any suitable form.

Figs. 7 and 8 represent the valves herein described, which are of a cylindrical form, with a cup or chamber, J, in the center. The hollow male screw Kis screwed into afemale screw cut in the base ofthe chamber-openin gs, as seen at K, Fig. 4. The top of this male screw forms an adjustable valve-seat for the valve I', Figs. 4, 5, and 7, to the top of which is the spring L, connected by any suitable means. The circumference of the piston is curved out to receive the spring L, as seen in Fig 4. By this arrangement the valves may be rendered adjustable, so as to be moved to or from the spring-packing, as may be required, and the said packing may rest upon a series of springs connected With each valve in the piston simi.- lar to that indioated in Figs. et and `7.

By means ot' the hollow screw K, Fig. 7, the valves may be raised or lowered, so as to set out or in the spring-paolini g, as required. All the Valves may be thus arranged in place of Athe single thiinhle or eup valve I, Fig. S, whieh in itself is substantially the same as the Valve l', only the latter is notas long by reason of the screw K taking up a portion of the lower part of the valve-chamber or opening. The steam enters the openings E or F, as the ease may he, and passes through the hollotv screw K and acts upon the valve I the same as the other valves. On `each side of the piston `is a circular groove, M. This groove forms adirect connection with the openings in the piston `and followers, and which allows the steam to pass around the grooves from one opening in the follower to the other, andl allowing afreepassage ot' the steam tothe openings in the vpiston as admitted through the follower-openings.

What We claim as our improvement, and

Titnesses W. H. BUnRiDen, A. W. MCCLELLAND. 

